Most of the time, my kids call me "Mom". Spencer will occasionally call me "Mommy" and he and Noah will sometimes call me "Mama", which I love. Annie started calling me "Mother" last fall. I'm not sure why, and it actually kind of bugged me at first, because I've never been a fan of the term mother. In my mind it seemed kind of cold and distanced. But the longer Annie has used it, the more I have come to like it. She doesn't mean it or use it in a cold way, but in a "Mom, I need you, I love you" kind of way. So it's ok. Stephen calls me "Mom" when he's right there with me, talking to me. But when he is looking for me, or needing me for something, he calls me "El Mamo" and I love it.
Spencer and I had a little conversation the other day which he started by saying, "Your name is Mom, but only your kids can call you Mom. What can other people's kids call you?"